From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andrew Cooper <andrew.cooper3@citrix.com>
Subject: Re: [PATCH 16/27] tools/libxl: Infrastructure for
 reading a libxl migration v2 stream
Date: Wed, 17 Jun 2015 10:50:29 +0100
Message-ID: <558142E5.1000609@citrix.com>
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To: Wen Congyang <wency@cn.fujitsu.com>, Xen-devel <xen-devel@lists.xen.org>
Cc: Ian Jackson <Ian.Jackson@eu.citrix.com>, Yang Hongyang <yanghy@cn.fujitsu.com>, Wei Liu <wei.liu2@citrix.com>, Ian Campbell <Ian.Campbell@citrix.com>, Ross Lagerwall <ross.lagerwall@citrix.com>
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On 17/06/15 08:57, Wen Congyang wrote:
>> +    /* Queue up reading the body. */
>> > +    size_t bytes_to_read;
>> > +
>> > +    switch (rec_hdr->type) {
>> > +        /*
>> > +         * Emulator records want to retain the blob in the pipe, for a further
>> > +         * datacopier call to move elsewhere.  Just read the emulator header.
>> > +         */
> In this case, we should not call ROUNDUP().
>
>> > +    case REC_TYPE_EMULATOR_CONTEXT:
>> > +        bytes_to_read = sizeof(struct libxl_sr_emulator_hdr);
>> > +        break;
>> > +
>> > +    default:
>> > +        bytes_to_read = rec_hdr->length;
>> > +        break;
>> > +    }
>> > +
>> > +    bytes_to_read = ROUNDUP(bytes_to_read, REC_ALIGN_ORDER);
> So, I think it is better to move ROUNDUP to default case.
>
> Thanks
> Wen Congyang
>

sizeof(struct libxl_sr_emulator_hdr) is cunningly of the appropriate
order already.

I suppose it is probably better to move the roundup into the default
case and assert() appropriate alignment after the switch()

~Andrew